// Beacon Daemon - collects events from scanners and uploads to server
package main

import (
	"context"
	"encoding/json"
	"flag"
	"fmt"
	"log"
	"net"
	"os"
	"os/signal"
	"strings"
	"sync"
	"syscall"
	"time"

	"github.com/go-zeromq/zmq4"
)

const (
	defaultConfigPath  = "/opt/mybeacon/etc/config.json"
	defaultStatePath   = "/opt/mybeacon/etc/device.json"
	defaultBinDir      = "/opt/mybeacon/bin"
	defaultWiFiIface   = "wlan0"
	maxSpoolBytes      = 100 * 1024 * 1024 // 100 MB
)

type Daemon struct {
	cfg       *Config
	state     *DeviceState
	client    *APIClient
	spooler   *Spooler
	tunnel    *SSHTunnel
	scanners  *ScannerManager
	api       *APIServer
	netmgr    *NetworkManager

	bleEvents  []interface{}
	wifiEvents []interface{}
	mu         sync.Mutex

	configPath string
	statePath  string

	stopChan chan struct{}
}

func main() {
	var (
		configPath = flag.String("config", defaultConfigPath, "Config file path")
		statePath  = flag.String("state", defaultStatePath, "Device state file path")
		serverAddr = flag.String("server", "", "API server address (e.g., http://192.168.5.2:5000)")
		binDir     = flag.String("bindir", defaultBinDir, "Directory with scanner binaries")
		wifiIface  = flag.String("wifi-iface", defaultWiFiIface, "WiFi interface for monitor mode")
		httpAddr   = flag.String("http", ":8080", "HTTP API listen address")
		debug      = flag.Bool("debug", false, "Enable debug logging")
	)
	flag.Parse()

	log.SetFlags(log.Ltime)
	log.Println("================================================================================")
	log.Println("Beacon Daemon starting...")

	// Load configuration
	cfg, err := LoadConfig(*configPath)
	if err != nil {
		log.Printf("Warning: failed to load config: %v (using defaults)", err)
		cfg = DefaultConfig()
	}
	cfg.Debug = *debug || cfg.Debug

	// Override server address if provided
	if *serverAddr != "" {
		cfg.APIBase = *serverAddr + "/api/v1"
		log.Printf("Using server: %s", *serverAddr)
	}

	// Store WiFi interface
	cfg.WiFiIface = *wifiIface

	// Load device state
	state, err := LoadDeviceState(*statePath)
	if err != nil {
		log.Printf("Warning: failed to load state: %v", err)
		state = &DeviceState{}
	}

	// Get device ID from MAC if not set
	if state.DeviceID == "" {
		state.DeviceID = getDeviceID()
		SaveDeviceState(*statePath, state)
	}
	log.Printf("Device ID: %s", state.DeviceID)

	// Create spooler
	spooler, err := NewSpooler(cfg.SpoolDir, maxSpoolBytes)
	if err != nil {
		log.Fatalf("Failed to create spooler: %v", err)
	}

	// Create SSH tunnel manager
	tunnel := NewSSHTunnel(cfg)

	// Create scanner manager
	scanners := NewScannerManager(*binDir, cfg.Debug)

	// Create network manager (manages eth0, wlan0 client, wlan0 AP fallback)
	netmgr := NewNetworkManager(cfg, scanners)

	// Create daemon
	daemon := &Daemon{
		cfg:        cfg,
		state:      state,
		client:     NewAPIClient(cfg.APIBase),
		spooler:    spooler,
		tunnel:     tunnel,
		scanners:   scanners,
		netmgr:     netmgr,
		configPath: *configPath,
		statePath:  *statePath,
		stopChan:   make(chan struct{}),
	}

	// Create API server
	daemon.api = NewAPIServer(daemon)

	if state.DeviceToken != "" {
		daemon.client.SetToken(state.DeviceToken)
	}

	// Handle signals
	sigChan := make(chan os.Signal, 1)
	signal.Notify(sigChan, syscall.SIGINT, syscall.SIGTERM)

	go func() {
		<-sigChan
		log.Println("Shutting down...")
		daemon.scanners.StopAll()
		daemon.tunnel.Stop()
		daemon.netmgr.Stop()
		close(daemon.stopChan)
	}()

	// Start HTTP API server FIRST (dashboard should be available immediately)
	go func() {
		log.Printf("Starting HTTP API server on %s", *httpAddr)
		if err := daemon.api.Start(*httpAddr); err != nil {
			log.Printf("HTTP server error: %v", err)
		}
	}()
	// Give HTTP server time to bind
	time.Sleep(100 * time.Millisecond)

	// Start network manager (manages eth0, wlan0 client, wlan0 AP fallback, WiFi scanner)
	// Network manager will automatically handle all network priorities and scanner coordination
	daemon.netmgr.Start()

	// Start SSH tunnel if enabled
	if cfg.SSHTunnel.Enabled {
		daemon.tunnel.Start()
	}

	// Start BLE scanner if enabled (not managed by network manager)
	if cfg.BLE.Enabled {
		if !daemon.scanners.IsBLERunning() {
			log.Println("Starting BLE scanner...")
			if err := daemon.scanners.StartBLE(cfg.ZMQAddrBLE); err != nil {
				log.Printf("Failed to start BLE scanner: %v", err)
			}
		}
	}

	// Start registration loop (if not registered)
	go daemon.registrationLoop()

	// Start config polling loop
	go daemon.configLoop()

	// Start ZMQ subscribers
	go daemon.subscribeLoop("ble", cfg.ZMQAddrBLE)
	go daemon.subscribeLoop("wifi", cfg.ZMQAddrWiFi)

	// Start batch upload loops
	go daemon.uploadLoop("ble", "/ble", cfg.BLE.BatchIntervalMs)
	go daemon.uploadLoop("wifi", "/wifi", cfg.WiFi.BatchIntervalMs)

	// Start spool flush loop
	go daemon.spoolFlushLoop()

	// Wait for shutdown
	<-daemon.stopChan
	log.Println("Daemon stopped")
}

// applyScannerConfig starts/stops scanners based on current config
func (d *Daemon) applyScannerConfig() {
	d.mu.Lock()
	bleEnabled := d.cfg.BLE.Enabled
	wifiMonitorEnabled := d.cfg.WiFi.MonitorEnabled
	wifiClientEnabled := d.cfg.WiFi.ClientEnabled
	zmqBLE := d.cfg.ZMQAddrBLE
	zmqWiFi := d.cfg.ZMQAddrWiFi
	wifiIface := d.cfg.WiFiIface
	d.mu.Unlock()

	// BLE scanner
	if bleEnabled {
		if !d.scanners.IsBLERunning() {
			log.Println("Starting BLE scanner...")
			if err := d.scanners.StartBLE(zmqBLE); err != nil {
				log.Printf("Failed to start BLE scanner: %v", err)
			}
		}
	} else {
		if d.scanners.IsBLERunning() {
			log.Println("Stopping BLE scanner...")
			d.scanners.StopBLE()
		}
	}

	// WiFi scanner - NEVER run if WiFi client is enabled (they share wlan0)
	// Client mode takes priority over monitor mode
	if wifiClientEnabled {
		if d.scanners.IsWiFiRunning() {
			log.Println("Stopping WiFi scanner (client mode enabled in config)...")
			d.scanners.StopWiFi()
		}
		return
	}

	// WiFi scanner - only if monitor enabled AND client disabled
	// Client has HIGHER priority - if both enabled, client works, scanner doesn't
	if wifiMonitorEnabled {
		if !d.scanners.IsWiFiRunning() {
			log.Println("Starting WiFi scanner...")
			if err := d.scanners.StartWiFi(zmqWiFi, wifiIface); err != nil {
				log.Printf("Failed to start WiFi scanner: %v", err)
			}
		}
	} else {
		if d.scanners.IsWiFiRunning() {
			log.Println("Stopping WiFi scanner (monitor disabled)...")
			d.scanners.StopWiFi()
		}
	}
}

// applyWiFiClientState checks if WiFi client state matches config and applies changes
func (d *Daemon) applyWiFiClientState() {
	d.mu.Lock()
	clientEnabled := d.cfg.WiFi.ClientEnabled
	ssid := d.cfg.WiFi.SSID
	psk := d.cfg.WiFi.PSK
	d.mu.Unlock()

	// Check if wlan0 has an IP (meaning it's connected)
	wlan0IP := getInterfaceIP("wlan0")
	isConnected := wlan0IP != ""

	if clientEnabled && ssid != "" {
		// Should be connected
		if !isConnected {
			// Stop WiFi scanner before connecting client (they can't coexist)
			if d.scanners.IsWiFiRunning() {
				log.Println("Stopping WiFi scanner before connecting client...")
				d.scanners.StopWiFi()
			}

			log.Printf("WiFi client should be connected (SSID=%s), connecting...", ssid)
			if err := applyWiFiSettings(ssid, psk); err != nil {
				log.Printf("Failed to connect WiFi client: %v", err)
			}
		}
	} else {
		// Should be disconnected
		if isConnected {
			log.Println("WiFi client should be disconnected, disconnecting...")
			disconnectWiFiClient()
		}
	}
}

func (d *Daemon) registrationLoop() {
	for {
		select {
		case <-d.stopChan:
			return
		default:
		}

		if d.state.DeviceToken != "" {
			time.Sleep(60 * time.Second)
			continue
		}

		log.Println("Attempting device registration...")
		req := &RegistrationRequest{
			DeviceID: d.state.DeviceID,
		}

		// Try to get IPs
		if ip := getInterfaceIP("eth0"); ip != "" {
			req.EthIP = &ip
		}
		if ip := getInterfaceIP("wlan0"); ip != "" {
			req.WlanIP = &ip
		}

		resp, err := d.client.Register(req)
		if err != nil {
			log.Printf("Registration failed: %v", err)
			time.Sleep(10 * time.Second)
			continue
		}

		d.state.DeviceToken = resp.DeviceToken
		d.state.DevicePassword = resp.DevicePassword
		d.client.SetToken(resp.DeviceToken)
		SaveDeviceState(d.statePath, d.state)
		log.Printf("Device registered, token received")
	}
}

func (d *Daemon) configLoop() {
	// Initial fetch immediately
	d.fetchAndApplyConfig()

	ticker := time.NewTicker(30 * time.Second)
	defer ticker.Stop()

	for {
		select {
		case <-d.stopChan:
			return
		case <-ticker.C:
		}

		d.fetchAndApplyConfig()
	}
}

func (d *Daemon) fetchAndApplyConfig() {
	if d.state.DeviceToken == "" {
		return
	}

	serverCfg, err := d.client.GetConfig(d.state.DeviceID)
	if err != nil {
		// In LAN mode, suppress errors (server might be unreachable)
		if d.cfg.Mode == "lan" {
			// Silent - use local config
			return
		}
		if d.cfg.Debug {
			log.Printf("Config fetch failed: %v", err)
		}
		return
	}

	// Determine effective mode: force_cloud overrides local mode setting
	effectiveMode := d.cfg.Mode
	if effectiveMode == "" {
		effectiveMode = "cloud"
	}
	if serverCfg.ForceCloud {
		if effectiveMode == "lan" {
			log.Println("Server force_cloud enabled - switching to cloud mode")
		}
		effectiveMode = "cloud"
	}

	d.mu.Lock()

	// Track changes for scanner restart
	bleChanged := false
	wifiMonitorChanged := false
	wifiClientChanged := false
	oldClientEnabled := d.cfg.WiFi.ClientEnabled

	if effectiveMode == "cloud" {
		// Cloud mode: server settings have priority
		bleChanged = d.cfg.BLE.Enabled != serverCfg.BLE.Enabled
		wifiMonitorChanged = d.cfg.WiFi.MonitorEnabled != serverCfg.WiFi.MonitorEnabled
		wifiClientChanged = d.cfg.WiFi.ClientEnabled != serverCfg.WiFi.ClientEnabled ||
			d.cfg.WiFi.SSID != serverCfg.WiFi.SSID ||
			d.cfg.WiFi.PSK != serverCfg.WiFi.PSK

		d.cfg.BLE.Enabled = serverCfg.BLE.Enabled
		d.cfg.BLE.BatchIntervalMs = serverCfg.BLE.BatchIntervalMs
		d.cfg.WiFi.MonitorEnabled = serverCfg.WiFi.MonitorEnabled
		d.cfg.WiFi.ClientEnabled = serverCfg.WiFi.ClientEnabled
		d.cfg.WiFi.SSID = serverCfg.WiFi.SSID
		d.cfg.WiFi.PSK = serverCfg.WiFi.PSK
		d.cfg.WiFi.BatchIntervalMs = serverCfg.WiFi.BatchIntervalMs
		d.cfg.Debug = serverCfg.Debug

		// NTP from server in cloud mode
		if len(serverCfg.Net.NTP.Servers) > 0 {
			d.cfg.Network.NTPServers = serverCfg.Net.NTP.Servers
		}
	}
	// LAN mode: local settings have priority, we keep what's in d.cfg
	// Only SSH tunnel comes from server (for remote support)

	// SSH tunnel ALWAYS from server (for remote support access)
	sshChanged := d.cfg.SSHTunnel.Enabled != serverCfg.SSHTunnel.Enabled
	if serverCfg.SSHTunnel.Enabled {
		d.cfg.SSHTunnel.Enabled = true
		d.cfg.SSHTunnel.Server = serverCfg.SSHTunnel.Server
		d.cfg.SSHTunnel.Port = serverCfg.SSHTunnel.Port
		d.cfg.SSHTunnel.User = serverCfg.SSHTunnel.User
		d.cfg.SSHTunnel.RemotePort = serverCfg.SSHTunnel.RemotePort
		d.cfg.SSHTunnel.KeepaliveInterval = serverCfg.SSHTunnel.KeepaliveInterval
	} else {
		d.cfg.SSHTunnel.Enabled = false
	}

	d.mu.Unlock()

	// Apply scanner config changes
	if bleChanged || wifiMonitorChanged {
		log.Printf("Config changed (mode=%s): ble=%v wifi_monitor=%v", effectiveMode, d.cfg.BLE.Enabled, d.cfg.WiFi.MonitorEnabled)
		d.applyScannerConfig()
	}

	// Apply WiFi client changes
	if wifiClientChanged {
		if d.cfg.WiFi.ClientEnabled && d.cfg.WiFi.SSID != "" {
			// Stop WiFi scanner before connecting client
			if d.scanners.IsWiFiRunning() {
				log.Println("Stopping WiFi scanner before connecting client...")
				d.scanners.StopWiFi()
			}

			log.Printf("WiFi client enabled by server: SSID=%s", d.cfg.WiFi.SSID)
			if err := applyWiFiSettings(d.cfg.WiFi.SSID, d.cfg.WiFi.PSK); err != nil {
				log.Printf("Failed to apply WiFi client settings: %v", err)
			}
			// After client connects, update scanner config (will skip WiFi scanner)
			d.applyScannerConfig()
		} else if oldClientEnabled && !d.cfg.WiFi.ClientEnabled {
			log.Println("WiFi client disabled by server")
			disconnectWiFiClient()
			// After client disconnects, WiFi scanner may start (if monitor enabled)
			d.applyScannerConfig()
		}
	}

	// Update tunnel config
	d.tunnel.UpdateConfig(d.cfg)
	if sshChanged {
		if d.cfg.SSHTunnel.Enabled {
			log.Println("SSH tunnel enabled by server")
			d.tunnel.Start()
		} else {
			log.Println("SSH tunnel disabled by server")
			d.tunnel.Stop()
		}
	}

	// Update network manager config (eth0 settings are local-only, never from server)
	d.netmgr.UpdateConfig(d.cfg)

	// Save updated config
	SaveConfig(d.configPath, d.cfg)
}

func (d *Daemon) subscribeLoop(name string, addr string) {
	for {
		select {
		case <-d.stopChan:
			return
		default:
		}

		// Only try to connect if the corresponding scanner is running
		scannerRunning := false
		if name == "ble" {
			scannerRunning = d.scanners.IsBLERunning()
		} else if name == "wifi" {
			scannerRunning = d.scanners.IsWiFiRunning()
		}

		if !scannerRunning {
			// Wait before checking again
			time.Sleep(5 * time.Second)
			continue
		}

		if err := d.runSubscriber(name, addr); err != nil {
			log.Printf("[%s] Subscriber error: %v, reconnecting...", name, err)
			time.Sleep(time.Second)
		}
	}
}

func (d *Daemon) runSubscriber(name string, addr string) error {
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	sub := zmq4.NewSub(ctx)
	defer sub.Close()

	// Subscribe to all topics for this type
	if err := sub.SetOption(zmq4.OptionSubscribe, name+"."); err != nil {
		return err
	}

	if err := sub.Dial(addr); err != nil {
		return err
	}

	log.Printf("[%s] Connected to %s", name, addr)

	// Monitor stop channel in goroutine
	go func() {
		<-d.stopChan
		cancel()
	}()

	for {
		msg, err := sub.Recv()
		if err != nil {
			return err
		}

		// Message is in first frame
		data := string(msg.Frames[0])

		// Parse message: "topic JSON"
		parts := strings.SplitN(data, " ", 2)
		if len(parts) != 2 {
			continue
		}

		var event interface{}
		if err := json.Unmarshal([]byte(parts[1]), &event); err != nil {
			continue
		}

		d.mu.Lock()
		if name == "ble" {
			d.bleEvents = append(d.bleEvents, event)
			if d.cfg.Debug {
				log.Printf("[%s] Received event, queue size: %d", name, len(d.bleEvents))
			}
			// Add to API for WebSocket broadcast
			if d.api != nil {
				d.api.AddBLEEvent(event)
			}
		} else {
			d.wifiEvents = append(d.wifiEvents, event)
			if d.cfg.Debug {
				log.Printf("[%s] Received event, queue size: %d", name, len(d.wifiEvents))
			}
			// Add to API for WebSocket broadcast
			if d.api != nil {
				d.api.AddWiFiEvent(event)
			}
		}
		d.mu.Unlock()
	}
}

func (d *Daemon) uploadLoop(name string, endpoint string, intervalMs int) {
	if intervalMs <= 0 {
		intervalMs = 2500
	}

	ticker := time.NewTicker(time.Duration(intervalMs) * time.Millisecond)
	defer ticker.Stop()

	for {
		select {
		case <-d.stopChan:
			return
		case <-ticker.C:
		}

		d.mu.Lock()
		var events []interface{}
		if name == "ble" {
			events = d.bleEvents
			d.bleEvents = nil
		} else {
			events = d.wifiEvents
			d.wifiEvents = nil
		}
		d.mu.Unlock()

		if len(events) == 0 {
			continue
		}

		if d.cfg.Debug {
			log.Printf("[%s] Batch ready: %d events, uploading...", name, len(events))
		}

		batch := &EventBatch{
			DeviceID: d.state.DeviceID,
			Events:   events,
		}

		if err := d.client.UploadEvents(endpoint, batch); err != nil {
			log.Printf("[%s] Upload failed: %v, spooling %d events", name, err, len(events))
			if err := d.spooler.Save(batch, name); err != nil {
				log.Printf("[%s] Spool save failed: %v", name, err)
			}
		} else {
			log.Printf("[%s] Uploaded %d events to server", name, len(events))
		}
	}
}

func (d *Daemon) spoolFlushLoop() {
	ticker := time.NewTicker(10 * time.Second)
	defer ticker.Stop()

	for {
		select {
		case <-d.stopChan:
			return
		case <-ticker.C:
		}

		if d.state.DeviceToken == "" {
			continue
		}

		// Try to flush one batch
		batch, err := d.spooler.PopOldest()
		if err != nil || batch == nil {
			continue
		}

		// Try to upload (guess endpoint from event types)
		endpoint := "/events"
		eventType := "unknown"
		if len(batch.Events) > 0 {
			if ev, ok := batch.Events[0].(map[string]interface{}); ok {
				if t, ok := ev["type"].(string); ok {
					if strings.HasPrefix(t, "wifi") {
						endpoint = "/wifi"
						eventType = "wifi"
					} else {
						endpoint = "/ble"
						eventType = "ble"
					}
				}
			}
		}

		if err := d.client.UploadEvents(endpoint, batch); err != nil {
			// Re-spool if upload failed
			d.spooler.Save(batch, "retry")
		} else {
			log.Printf("[spool] Flushed %d %s events to server", len(batch.Events), eventType)
		}
	}
}

// getDeviceID returns a device ID based on MAC address
func getDeviceID() string {
	// Try wlan0 first, then eth0
	for _, iface := range []string{"wlan0", "eth0"} {
		if mac := getInterfaceMAC(iface); mac != "" {
			return mac
		}
	}
	// Fallback to hostname
	host, _ := os.Hostname()
	return host
}

func getInterfaceMAC(name string) string {
	iface, err := net.InterfaceByName(name)
	if err != nil {
		return ""
	}
	return iface.HardwareAddr.String()
}

func getInterfaceIP(name string) string {
	iface, err := net.InterfaceByName(name)
	if err != nil {
		return ""
	}
	addrs, err := iface.Addrs()
	if err != nil {
		return ""
	}
	for _, addr := range addrs {
		if ipnet, ok := addr.(*net.IPNet); ok && ipnet.IP.To4() != nil {
			// Return IP with CIDR notation (e.g., 192.168.5.244/24)
			ones, _ := ipnet.Mask.Size()
			return fmt.Sprintf("%s/%d", ipnet.IP.String(), ones)
		}
	}
	return ""
}